Dual-Spring Face Seal Assembly for Wear-Stable Axial Force

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Face seal failure in gas turbine engines due to premature sealing face wear leads to increased engine system risk and damage to surrounding hardware, as the spring load reduction exacerbates wear and damage over time.

Innovation Solution

The introduction of a dual-spring mechanism where first springs bias the seal housing away from the support and second springs, circumferentially offset and extending along retention pins, counteract the first springs to maintain a consistent net axial force on the seal seat, reducing wear and damage by adjusting the seal's axial force dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single spring is used to bias the seal housing toward the seal support, then the seal maintains initial contact force, but the spring load reduces over time due to wear and translation, leading to seal failure

Engineering Contradiction:

Improveseal reliabilityVSAvoidseal lifespan

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The single spring system is segmented into two separate spring systems: first springs that bias the seal housing away from the seal support, and second springs that bias the seal housing toward the seal support. This segmentation allows independent optimization of each spring's function, with the second springs specifically designed to compensate for wear-induced translation and maintain consistent seal contact force throughout the seal's operational life.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the spring force parameters dynamically through the dual-spring configuration. The second springs are designed with specific stiffness and preload characteristics that counteract the wear-induced relaxation of the first springs, maintaining a relatively constant net axial force on the seal seat throughout the seal's operational life, thereby extending seal lifespan while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

2Force

If spring load is increased to prevent seal wear, then seal contact force is improved, but the reduced spring load after wear leads to more severe damage and higher engine system risk

Engineering Contradiction:

Improveseal contact forceVSAvoidseal damage and engine system risk

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The second springs are pre-configured to provide a counteracting force that compensates for the anticipated wear-induced relaxation of the first springs. This preliminary anti-action ensures that as the seal wears and translates axially, the second springs progressively engage to maintain consistent contact force, preventing the dangerous reduction in spring load that would otherwise lead to severe damage and engine system failure.

Inventive Principle:

Principle #9Preliminary anti-action

3Length of moving object

If the seal housing is allowed to translate axially due to wear, then the spring extends and maintains some contact, but the spring load reduces to levels that cause continued wear and severe damage

Engineering Contradiction:

Improvespring lengthVSAvoidseal reliability

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The second springs act as a counterweight system that balances the axial translation caused by wear. As the seal housing translates axially due to wear, the second springs compress to provide a counteracting force that maintains consistent net axial force on the seal seat, preventing the spring load reduction that would otherwise lead to continued wear and seal failure, thereby maintaining reliability throughout the seal's operational life.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design reduces the rate of seal failure and maintenance needs by maintaining optimal axial force on the seal seat, improving durability and reducing maintenance costs by mitigating the effects of seal wear and extending the seal's lifespan.

Implementation Method 1

One or more first springs extend between the seal support and the second axial surface to urge the seal housing away from the seal support

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

one or more second springs are located at the first axial surface to urge the seal housing toward the seal support

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS11549384B2Face seal arrangement

Publication Date: 2023.01.10 RTX CORP

AI summary

A seal assembly includes an annular seal support, and an annular seal housing operably connected to the seal support. The seal housing includes a first axial surface facing away from the seal support, and a second axial surface opposite the first axial surface. A seal is located at the first axial surface. One or more first springs extend between the seal support and the second axial surface to urge the seal housing away from the seal support, and one or more second springs are located at the first axial surface to urge the seal housing toward the seal support.